The Biostatistics Core has the following specific aims: 1) Provide biostatistical expertise for the design, management and analysis of Alzheimer's Disease Cooperative Study (ADCS) clinical investigations and 2) Generate randomization sequences for treatment allocation for all ADCS RCTs. More specifically the Biostatistics Core is charged with the following responsibilities: Study Design, Development, and Implementation, Study Analysis and Closeout, and External Collaborations.